Epoxy resins have a broad range of physical characteristics and, because of this, they are used in many industrial applications. Epoxy resins have at least one epoxy group which can be converted to a thermoset form having desirable properties. These epoxy groups may be cured by the use of a catalyst or a curing agent. The curing may be accelerated by the addition of small but effective amounts of accelerating agents.
There are many different types of curing agents which may be utilized. Amines and, more specifically, aliphatic amines are commonly employed as curing agents. For example, diethylenetriamine, triethylenetetramine and polyoxyalkylene polyamines such as polyoxypropylene-diamines and triamines have been utilized as curing agents.
The physical properties of epoxy resin compositions have been improved by using curing agents such a polyoxyalkylene-amines and, in particular, polyoxyalkylenediamines. Physical properties of epoxy resin compositions have also been improved by using co-curing agents such as those described in U.S. Pat. No. 3,549,592. Ureas and substituted areas have been utilized as epoxy curing agents, co-curing agents and curing accelerators. These urea and substituted urea compounds have been disclosed in U.S. Pat. Nos. 3,294,749; 2,713,569; 3,386,956; 3,386,955; 2,855,372; and 3,639,338.
Compounds having a single terminal ureido group have been disclosed in U.S. Pat. Nos. 2,145,242 and 3,965,072.